Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=false, idempotentHint=false, and destructiveHint=false, so the description's non-idempotency note is partly redundant — but spelling out the concrete consequence ('calling twice creates two students') is a real value-add beyond the hint flag. It also contributes the 'existing family' prerequisite that no annotation conveys.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two compact clauses, front-loaded with the operation class and verb, with zero filler. Every element (mutation status, target entity, idempotency consequence, requirement, endpoint) carries information.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no output schema, the description is silent on what a create call returns — notably whether the new student's id comes back, which an agent needs to chain into follow-up calls. For a 10-parameter mutation tool this leaves a meaningful gap, though annotations cover the safety profile.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100% and every property is documented, so the schema does the heavy lifting. The description only restates the two required fields (family_id, first_name) already marked required in the schema, adding no format or lookup guidance beyond what's there.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('add a new student to an existing family in Jackrabbit') plus the HTTP endpoint, which is enough to distinguish it from jackrabbit_get_student and jackrabbit_create_waitlist_entry. The 'WRITE:' prefix immediately signals the operation class.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It gives a usable precondition ('existing family', requires family id and first name), which implies usage but never states when to use this versus the sibling write tool (jackrabbit_create_waitlist_entry) or to look up a family first. No explicit exclusions or alternative routing.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.